I've been running PP CS6 almost without incident since August. Yesterday I was working on a short collection of excerpts to post on vimeo, all of it was material that I had edited without any issues in the past, shot on AVCHD last march. After a CC pass I like to render all the effects in the sequence to do few playback reviews, the effects render started crashing, I thought it was pretty odd because there is a total of maybe 4 transition effects in the entire sequence beyond the CC on about 1/2 of the clips in the 2 minute sequence. After several hours of trying different things I think I isolated it to a cross dissolve into and out of a short piece of aerial footage. I tried transcoding the offending clip (but I didn't go so far as transcoding the clips on either side). After spending way too much time trying to diagnose the problem I ended up faking the transition effect with keyframing opacity in and out of the clip, and then it rendered flawlessly!
SYSTEM:
-PP CS6 updated
-win7 64 updated
-ASUS P6t mb
-16gb ram
-gtx470 gpu
-The original media is on an eSATA hdd, I cloned copies of the media to an internal drive, no joy.
-Rebuilt the original sequence in a new sequence, no joy.
The only thing slightly "hinky" in this is that I am using a custom 2:35 aspect sequence, 1280X535 24p to be exact.